One aspect of contemporary dental surgery involves the use of prosthetic teeth to replace missing teeth. Typically one or more prosthetic teeth are mounted on dental implants which are secured in the jawbone of the recipient. The dental implants must be securely mounted in sufficient bone tissue so that they are as stable as natural teeth roots.
The conventional procedure for installing a dental implant includes drilling a hole in the maxillary or mandibular jawbone of the recipient, inserting the implant in the hole, and attaching a prosthetic tooth to the implant. Various types of dental implants are useful; for example, blades, screws, and cylinders. The dental implant is generally made of titanium or high titanium alloy and the top of the dental implant, which is typically located at the gingiva, is provided with a mating means (usually a top portion and inner threads) for attaching the prosthetic tooth thereto.
The osteotomy must be located the correct distance from adjacent teeth in order to guarantee a proper fit and cosmetic result for the prosthetic device. Furthermore, it is extremely important to accurately locate the osteotomy in the jawbone so that the implant is sufficiently anchored in the bone structure.
Because of the limited space, working within a patient's mouth poses many impediments to easily and precisely locating and making the osteotomy for the implant, and ultimately positioning the prosthetic.
It is known in dental surgery to make a cast impression of the patient's mandible and/or maxilla in order to design or select the appropriate prosthetic device. Moreover, it is known to use the diagnostic tooth set-up or wax-up on a cast to determine the most desirable tooth position in the final restoration. In locating and creating the hole for a dental implant, however, the most commonly used method is simply to survey the area visually and drill according to the visual inspection. In some cases, where the patient is completely or significantly toothless, an acrylic tooth set-up may be used in the patient's mouth to locate the most desirable tooth position in the final restoration. With acrylic tooth set-ups, the surgeon drills through the tooth set-up in order to make a mark on the patient's jawbone. The acrylic set-up is then removed, and the mark is used as the start of the hole for the implant. In other words, the surgeon continues drilling the started hole at a visually determined angle.
Other techniques for locating dental implants are available. For example, U.S. Pat. No. 5,015,183 to Fenick describes a method involving the use of a casting having a radiopaque marker which is inserted into the patient's mouth. A series of x-rays is taken to establish a trajectory for the proposed osteotomy in the patient's jawbone. While the method provides an accurate means to locate the implant hole, it requires multiple x-rays subjecting the patients to undesirable exposure levels, and is expensive.
U.S. Pat. No. 5,556,278 to Meitner describes a method for locating a dental implant hole in a patient's jawbone by constructing a template and using a guide post and a sleeve. However, because of the length or height of the sleeve, it is difficult to Insert the drill bit th rough the top of the sleeve bore and to maneuver the drill bit as a significant amount of space within a patient's mouth is required.
What is needed then is a method and apparatus for accurately, safely, and conveniently locating an osteotomy for a dental implant in the mouth of the implant recipient.